10034.cpp

/**
 *                                   ____
 *       ____ ___  ____ ________  __/ __/
 *      / __ `__ \/ __ `/ ___/ / / / /_
 *     / / / / / / /_/ / /  / /_/ / __/
 *    /_/ /_/ /_/\__,_/_/   \__,_/_/
 *
 *    @link : https://the-redback.com
 */
#include <bits/stdc++.h>
using namespace std;

#define inf       10000000
#define mem(a, b) memset(a, b, sizeof(a))
#define NN        111

struct edge {
    int u, v;
    double w;
};
struct node {
    double x, y;
};
node a[NN + 7];
int pr[NN + 7];
vector<edge> e;
bool comp(edge n, edge m) { return n.w < m.w; }

int root(int n) {
    if (pr[n] == n) return n;
    return root(pr[n]);
}
double mst(int n) {
    int i, j, k;
    for (i = 0; i <= n; i++) pr[i] = i;
    sort(e.begin(), e.end(), comp);
    int count = 0;
    double sum = 0;
    for (i = 0; i < e.size() && count < n - 1; i++) {
        int u = root(e[i].u);
        int v = root(e[i].v);
        if (u != v) {
            pr[u] = v;
            count++;
            sum += e[i].w;
        }
    }
    return sum;
}

int main() {
    // freopen("C:\\Users\\Maruf Tuhin\\Desktop\\in.txt","r",stdin);
    // ios_base::sync_with_stdio(false);
    int i, j, k, l, n, r, c, u, v, w;
    edge ed;
    node nd;
    int tc, t = 1, m;
    double x;
    scanf("%d", &tc);
    while (tc--) {
        scanf("%d", &n);
        for (i = 1; i <= n; i++) scanf("%lf%lf", &a[i].x, &a[i].y);
        for (i = 1; i <= n; i++)
            for (j = i + 1; j <= n; j++) {
                x = ((a[i].x - a[j].x) * (a[i].x - a[j].x)) + ((a[i].y - a[j].y) * (a[i].y - a[j].y));
                x = sqrt((double)x);
                ed.u = i;
                ed.v = j;
                ed.w = x;
                e.push_back(ed);
            }
        double sum = mst(n);
        if (t != 1) puts("");
        t++;
        printf("%.2lf\n", sum);
        e.clear();
    }
    cin >> n;

    return 0;
}